Feline leukemia virus (FeLV) is responsible for feline leukemia syndrome in domestic cats. The prevention and control of disease caused by FeLV are primarily based on vaccination and identification and isolation of infected subjects. Antigen diagnostic methods, which are the most widely used in clinical practices, can be associated to molecular tests to characterize the FeLV detected. In this study, a quantitative SYBR Green Real-Time PCR (qPCR) assay was used to detect FeLV proviral DNA in blood samples from antigen positive cats referred to a veterinary teaching hospital in Northern Italy in 2018–2021. To genetically characterize the identified viruses, a portion of the viral envelope (env) gene was amplified using six different end-point PCRs and sequenced. Twenty-two of 26 (84.6%) cats included in the study tested positive by qPCR assay. This suggests a high performance of the qPCR adopted but further studies are required to investigate the cause of discordant results between the antigen test and qPCR in four cats. From env gene analysis, 15/22 qPCR-positive cats were infected by FeLV subtype A and 5/15 shown coinfection with subtype B.

猫白血病病毒 (FeLV) 是导致家猫患猫白血病综合征的原因。 FeLV引起的疾病的预防和控制主要基于疫苗接种以及感染者的识别和隔离。临床实践中应用最广泛的抗原诊断方法可以与分子测试相关联，以表征检测到的 FeLV。在本研究中，采用定量 SYBR Green 实时 PCR (qPCR) 检测方法检测 2018-2021 年转诊至意大利北部兽医教学医院的抗原阳性猫血液样本中的 FeLV 前病毒 DNA。为了对已识别的病毒进行遗传表征，使用六种不同的终点 PCR 扩增病毒包膜 ( env ) 基因的一部分并进行测序。研究中的 26 只猫中有 22 只 (84.6%) 通过 qPCR 检测呈阳性。这表明所采用的 qPCR 具有高性能，但需要进一步研究来调查四只猫的抗原测试和 qPCR 结果不一致的原因。根据env基因分析，15/22 的 qPCR 阳性猫被 FeLV A 亚型感染，5/15 显示与 B 亚型同时感染。